There is no easy, one-step way to quickly snap an image of what's on your display in Android
Although the feature isn't built into the operating system, you don't have to root your Android device in order to capture a screenshot. Follow these instructions if you must have a screen grab:
1. First download and install the Android SDK on your computer.
2. Also make sure you have the latest version of the JRE (Java Run Time Environment).
3. Connect your Android device to the computer.
4. Navigate to Settings -> Applications -> Development and turn on USB Debugging on your Android device.
5. Run the ddms tool. On a Windows computer, navigate to the Android SDK\tools folder and double click the ddms.bat file. For Mac OS X or Linux enter ./ddms in the sdk/tools directory from the command line of a terminal window.
6. Select your Android device in the left panel of the ddms application.
7. Choose Device -> Screen Capture from the top menu bar or press Control + S to open the screen capture window.
8. Click the Refresh button until you're happy with the screenshot then click Save.
You can rotate image orientation, copy the captured images to the clipboard, or save a file to the directory of your choice using the buttons in the Device Screen Capture window.